There are many different kinds of food packages, but of particular relevance to this disclosure are food packages of a type generally comprising a plastic tray formed with adjacent but separate compartments, each such compartment having a top opening for receiving a different food product and all of the openings of such compartments being covered by a thin flexible film. An example of such a tray is shown in U.S. Pat. No. 4,013,798.
Sometimes trays of this type are put in boxes, some are fitted with rear panels and others are surrounded by a collar. These devices serve the purpose of providing a substrate for written product information and advertising, of providing protection for the tray during handling, and sometimes providing a means for having the tray stand upright for display on a shelf. U.S. Pat. No. 5,042,652 shows a stiff collar wrapped around the tray sufficiently tightly that it will not slide off the tray due to frictional engagement between the collar and the tray.